1. Field of the Invention
The present invention relates to die cast heat treated aluminum silicon based alloys and processes for forming the same.
2. Description of the Prior Art
Alloys which fall within the compositional range of the present invention are known. For example, the commercial alloy A-390 is preferred for use in the present invention.
The heat treatment regimen of the present invention is also known; it is described in Japanese Industrial Standard T6 (hereafter JIS T6).
Further, two step die casting is also known. Such is described in, for example, U.S. Pat. No. 3,106,002 Bauer, hereby incorporated by reference and U.S. Pat. No. 4,380,261 Suzuki et al later discussed.
U.S. Pat. No. 3,664,410 Groteke relates to a metal casting method and apparatus directed to minimizing the formation of voids and improving the quality of cast products. The casting mold is provided with an opening, preferably adjacent to a "hot spot" of the casting space, where the poured metal would be expected to solidify at a relatively slower rate so that some of the molten metal will reach through and beyond the opening and form a metallic nib or projection. The casting equipment is operated to drive a movable rod against the nib to force it through the opening surface and into pressurized contact with the casting material to overcome the voids which would otherwise be produced within the cast product.
U.S. Pat. No. 3,792,726 discloses a metal surface strengthening method comprising attaching, with or without pressure, a preformed plate formed of a metal surface strengthening powder to a molten metal kept in a gas sprayed protective atmosphere in the mold.
U.S. Pat. No. 3,815,663 discloses die casting apparatus of a conventional nature.
U.S. Pat. No. 3,895,941 Bolling deals with aluminum silicon alloys which comprise primary and eutectic silicon simultaneously finely divided and uniformily distributed throughout a casting thereof. The alloys are described as having improved wear resistance, machinability and mechanical properties.
U.S. Pat. No. 4,055,417 Komiyama et al discloses hypereutectic aluminum silicon based alloys for casting. The alloys are characterized as having improved strength, improved machinability and improved wear resistance. The alloys, which are adapted for casting, consist essentially of 16 to 25% silicon, 3.0 to 5.5% copper, 0.2 to 0.8% magnesium, 0.3 to 0.8% manganese, not more than 0.25% of titanium, not more than 0.3% of iron, balance aluminum.
U.S. Pat. No. 4,113,473 Gauvry et al discloses a process for obtaining blanks for extrusion by impact, the blanks being an aluminum alloy containing a large quantity of silicon. The product is indicated to be particularly suitable for manufacturing linings for internal combustion engines.
U.S. Pat. No. 4,347,046 Brucken et al discloses a swash plate compressor of light weight.
U.S. Pat. No. 4,380,261 Suzuki et al discloses a die-casting method in which a molten metal is injected by an injection plunger into a die cavity through an injection passageway and the molten metal injected into the die cavity is squeezed by a squeeze plunger movable through a squeeze passage provided separately from the portion through which the molten metal has been injected into the die cavity. Suzuki et al is also hereby incorporated by reference.
U.S. Pat. No. 3,536,123 Izumi relates to an internal combusion engine cylinder characterized in that it is made of a centrifugally cast high silicon aluminum alloy in which the silicon content is made high in the inside part but low in the outside part. By increasing the content of silicon only on the inside surface wear resistance is improved but by maintaining the silicon content low on the outside surface thermal conductivity and toughness are improved.
U.S. Pat. No. 3,613,768 Awano et al generally deals with a liquid metal forging process comprising pouring liquid metal into a mold, applying high pressure by a punch to the liquid metal through a sealing member where, during pressing, the rim of the sealing member deforms and closely fits the mold to seal the member between the punch and the mold, thereby preventing flash.